Field of the Disclosure
The present disclosure relates generally to cameras and, more particularly, to calibration of cameras.
Description of the Related Art
Three-dimensional (3-D) camera vision systems use a model of a camera to relate objects in the 3-D space to the two-dimensional (2-D) image formed by the objects on an image plane in the camera. Model parameters include intrinsic parameters that are used to characterize each individual camera. Intrinsic parameters include a focal length of the camera lens, a center of projection of the lens, one or more distortion coefficients, and scaling of the image in the X direction and the Y direction. The model parameters also include extrinsic parameters (which may be referred to as poses) that characterize the translation and rotation of one or more cameras relative to the calibration targets. For example, the extrinsic parameters of an individual camera (or camera rig including multiple cameras) include the X, Y, and Z coordinates that define the translation of the camera and the pitch, roll, and yaw values that define the rotation of the camera relative to the target. Additional extrinsic parameters can be used to characterize the relative translation or rotation of multiple cameras that are rigidly attached to each other in a camera rig. Further extrinsic parameters include parameters that describe the relative position and orientation of multiple calibration targets that are rigidly attached to each other. The extrinsic parameters may also include contextual information such as an ambient lighting condition, a time of day, a weather condition, and the like.